The present invention relates to a process for producing L-tryptophan by culturing a microorganism belonging to the genus Corynebacterium or Brevibacterium, and having resistance to an aminoquinoline derivative or a phenothiazine derivative and an ability to produce L-tryptophan. L-Tryptophan is an amino acid which is useful as a medicament or as food and an additive for animal feed.
Heretofore, various processes for producing L-tryptophan by culturing a Coryneform gultamic acid-producing bacterium are known; for example, a process by use of a microorganism belonging to the genus Corynebacterium, requiring L-tyrosine and L-phenylalanine for growth and having resistance to at least one of tyrosine analogs and phenylalanine analogs (Japanese Published Examined Patent Application No. 19037/76); a process by use of a microorganism having resistance to a tryptophan analog such as 5-methyltryptophan, etc. (Japanese Published Examined Patent Application Nos. 18828/73, 38795/76 and 39517/78); a process by use of a histidine auxotroph (Japanese Published Examined Patent Application No. 4505/72); a process by use of a microorganism belonging to the genus Brevibacterium which is decreased or lacking in pyruvate kinase activity (Japanese Published Unexamined Patent Application No. 253391/87); a process by use of a microorganism belonging to the genus Corynebacterium which is decreased or lacking in phosphoenolpyruvate carboxylase activity (Japanese Published Unexamined Patent Application No. 317395/89); etc. An efficient process for producing L-tryptophan is always in demand from an industrial view point.